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| 基坑开挖卸荷引起下覆隧道上浮隆起的控制方法 |
| Control Methods for Uplift and Heave of Underlying Tunnels Caused by Unloading Due to Foundation Pit Excavation |
| 投稿时间：2025-06-09 修订日期：2025-09-26 |
| DOI： |
| 中文关键词: 开挖卸荷 基坑降水 堆载反压 上浮隆起 有限元分析 |
| 英文关键词: Excavation and load relief dewatering of foundation pit Overburden counterpressure Upward bulge Finite element analysis |
| 基金项目:国家自然科学基金项目（面上项目，重点项目，重大项目） |
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| 中文摘要: |
| 随着城市地下空间开发强度不断提升，上跨基坑工程与下覆既有隧道近接施频繁，基坑开挖与降水引起土体应力释放和地下水位变化都会导致下覆隧道的上浮和沉降，严重时会对隧道衬砌结构造成损伤。以厦门北站交通综合配套工程为工程实例，通过Midas gts nx建立三维数值模型，对比分析不同开挖顺序、降水深度、隧道内堆载量与堆载位置对下覆隧道变形的影响。研究结果表明：分块开挖通过分段式卸荷降低隧道上浮位移，其中先开挖远隧道侧土体为最优开挖方案，降水深度控制在坑底以下4 m处可平衡隧道中部隆起变形和两端固结沉降，采用均布堆载加线性堆载90 kPa的组合堆载方式，双线隧道最大竖向位移分别降低9.69%、7.67%，以开挖的时空效应-降水深度优化-堆载反压的综合控制方法，有效控制隧道上浮且未对衬砌结构造成损伤，为类似基坑与隧道近接施工工程提供参考。 |
| 英文摘要: |
| With the continuous increase in the intensity of urban underground space development. Excavation pits are frequently constructed above existing underlying tunnels at close proximity. Excavation and dewatering of foundation pits lead to soil stress release and groundwater level changes, both of which can cause heaving and settlement of the underlying tunnels. In severe cases, it can cause damage to the tunnel lining structure. Taking the comprehensive transportation infrastructure project of Xiamen North Railway Station as an example. A three-dimensional numerical model was established using Midas gts nx. The comparative effects of different excavation sequences, dewatering depths, and internal tunnel loading on underlying tunnel deformation. The results indicate that:Block excavation reduces the uplift displacement of the tunnel through staged unloading. Among which excavating the soil on the side farther from the tunnel first proved to be the optimal construction scheme.Controlling the dewatering depth to 4 meters below the pit bottom can strike a balance between the heave deformation in the central section of the tunnel and the consolidation settlement at its ends.Employing a combined loading method of uniform load plus a 90 kPa linear load.The maximum vertical displacements of the twin tunnels are reduced by 9.69% and 7.67%, respectively.A comprehensive control method integrating the spatio-temporal effects of excavation, optimized dewatering depth, and counterweight loading was established.This approach effectively controlled tunnel heaving and incurred no damage to the lining structure.This study can provide a valuable reference for similar projects involving foundation pits constructed in close proximity to existing tunnels. |
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